02 Commercial Ship & Fluiddynamics
Our services for commercial ship design and fluiddynamics.
Hull design
Hull Form Design Using Advanced CFD
ACT provides hull form design and development services for commercial ships, delivering superior hydrodynamic performance, low resistance, and high propulsion efficiency, while fully satisfying operational and design constraints.
We have one of the longest histories in CFD-based ship hull design, having started the application of CFD to hull form development in 1993.
Through decades of practical use, we have accumulated extensive know-how, validated methodologies, and proven results.
By applying CFD at the early design stage, we can efficiently evaluate a wide range of hull form candidates prior to model tank testing, significantly reducing both development time and cost while improving final performance.
Track Record in Commercial Ship Design
Since 2006, we have been providing advanced hull form design services to shipbuilding yards and shipping companies worldwide.
Across all projects, we have consistently achieved 3–15% reductions in Brake Horsepower (BHP) compared with existing vessels of similar type.
For typical bulk carriers with daily fuel consumption of approximately 20–50 tons/day, even a 5% BHP reduction translates into fuel savings of 1–2.5 tons per day, delivering significant operational cost and emissions reductions throughout the vessel’s service life.
Selected Design Experience
Autonomous and Advanced Vessels
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Autonomous Surface Vessels (ASVs)
Since 2019, we have been engaged in hull form development for ASVs.
High-Speed and Specialized Craft
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High-speed Hydrofoil Catamarans (foil system & hull design)
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32m type: launched in 2025, commercial service on the Hiroshima–Matsuyama route
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28m type: launched in 2023, currently in commercial service (Hiroshima–Etajima)
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37m type: launched in 2021, in commercial service on the Naha–Zamami route (Okinawa)
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30m type: launched in 2017, in commercial service in Nagasaki
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Crew Transfer Vessel (CTV) hull design
Commercial Ships
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Bulk Carriers
Hull designs for more than 30 vessels, ranging from Handy size to Cape size. -
Container Ships
Hull designs for over 20 vessels, from 1,000 TEU to 9,300 TEU class.
Consultancy on fluiddynamics
ACT provides advanced fluid-dynamics consultancy, delivering optimum solutions through deep expertise in CFD and related numerical tools.
CFD is one of our core strengths, and through extensive experience and accumulated know-how, we apply it efficiently and effectively to a wide range of complex engineering problems.
Our consultancy track record includes:
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Wind-assisted propulsion systems
Lead CFD-based wing sail design and performance prediction for the Wind Challenger Project since 2009 as a founding member, using CFD and EPP (Energy Prediction Program).
Results demonstrated an average BHP reduction exceeding 20%, reaching approximately 50% under 20-knot beam wind conditions. -
Integrated sail and hull form development
For the subsequent Wind Hunter Project, conducted sail arrangement design and catamaran hull-form development as part of a joint research program with MOL. -
Propulsion efficiency enhancement devices
Developed multiple stern-region devices to improve propulsion efficiency.
A stator-fin system installed on the propeller boss of a bulk carrier achieved approximately 5% BHP reduction. -
Aerodynamic drag reduction of ship superstructures
Analyzed wind-induced pressure drag on container ships and PCCs, and developed new superstructure shapes achieving over 20% drag reduction. -
Unsteady CFD for sports engineering applications
Conducted unsteady CFD analysis to clarify the operating mechanism of the SRD device developed by SHIMANO INC. for rowing-boat foot stretchers.
Software development & consultancy
ACT has developed various kinds of software to improve design work efficiency. Some of the software has been provided to clients for their design work. We also support the system integration for the design-by-CFD by developing and customizing design software and providing necessary training for effective usage.
Our served software includes the following;
HullDes/AutoDes – An Innovative Hull Design Support Program
HullDes/AutoDes is an innovative hull design support program jointly developed by ACT and NMRI.
While conventional design processes required enormous manual work and countless trial-and-error steps, AutoDes enables a fully automated workflow from hull form modification to CFD analysis and optimization. Designers can now achieve hull development with unprecedented speed and accuracy.
One of its most remarkable features is the optimization capability incorporating a proprietary discrete SQP method. By manipulating parametric variables or distribution functions within specified regions, hull forms can be flexibly deformed. In combination with CFD, the system automatically performs iterative calculations and optimizations, ultimately leading to the most efficient hull design.
Key Features
Flexible Data Input/Output
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Import/export multiple NURBS hull surfaces in srf (FastShip) or IGES format
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Conversion from IGES to NAPA format
Advanced Hull Form Modification
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Freely modify key parameters such as Cp, LCB, frame lines, and local geometry
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Box-type deformation within designated regions
Automated Mesh Generation
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Automatic generation of O-H/O-O type structured meshes for CFD
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Surface clustering and special transom treatments
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High-speed parallel processing with OpenMP
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Overset grid generation including rudders, fins, ducts, and appendages
Analysis & Optimization
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Seamless CFD integration with NMRI’s Neptune, Surf, and Nagisa
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Automatic hull deformation and optimization using the proprietary SQP method
Fully Automated Workflow
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From hull form modification → CFD analysis → optimization, the entire multi-step process is automated
Proven Performance
HullDes/AutoDes has already been adopted by over 20 shipyards and consulting firms, delivering tangible results in real-world projects.
It represents a new era of design support tools, combining the intuition and experience of designers with scientifically grounded optimization to deliver superior hull solutions.
For further details, please contact NMRI.
CFD and FEM interaction system
Waterbag deformation prediction software can simulate the towed waterbag deformation due to static and dynamic water pressure. The CFD and FEM iteration technique is used.
SpinFlow software can simulate the flow around a spinnaker and a main sail on a sailing yacht. The flying sails should deform according to the air pressure. The dynamic deformation of the sails can be achieved by FEM as a function of the SpinFlow. The iterative work between the CFD and the FEM can be automatically carried out until the deformation has converged. The GUI is provided for the pre and post processes in which the mesh is automatically created. The results are also visualized in the post process functions.
ParaFlow software can simulate the flow around a parachute to evaluate the fluid dynamic forces acting on the surface. The system is very similar to the above SpinFlow. The boundary conditions for the ventilation and the permeable areas can be set easily on the view window of the GUI.
